package com.feige.utils.verifycode;

import cn.hutool.core.codec.Base64;

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.security.SecureRandom;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

/**
 * @author feige
 */
public class GenerateVerifyCodeImg {

    /**
     * 使用到Algerian字体，系统里没有的话需要安装字体，字体只显示大写，去掉了1,0,i,o几个容易混淆的字符
     */
    public static final String VERIFY_CODES = "123456789ABCDEFGHJKLMNPQRSTUVWXYZ";
    public static final String[] ARITHMETIC_SYMBOLS = {"+", "-", "*", "/"};
    public static final String EQUALS = "=?";
    public static final int[] NUMBER = {1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 10};
    private static final Random random = new SecureRandom();
    public static final int W = 111;
    public static final int H = 36;
    private static int[] getNumber() {
        Random random = new Random();
        int[] values = new int[2];
        for (int i = 0; i < 2; i++) {
            int nextInt = random.nextInt(NUMBER.length);
            values[i] = NUMBER[nextInt];
        }
        return values;
    }

    private static String getSymbol() {
        Random random = new Random();
        int nextInt = random.nextInt(ARITHMETIC_SYMBOLS.length);
        return ARITHMETIC_SYMBOLS[nextInt];
    }

    private static String[] getResult(int[] values) {
        String symbol = getSymbol();
        String[] result = new String[2];
        if (ARITHMETIC_SYMBOLS[0].equals(symbol)) {
            result[0] = String.valueOf(values[0] + values[1]);
        } else if (ARITHMETIC_SYMBOLS[1].equals(symbol)) {
            if (values[0] >= values[1]) {
                result[0] = String.valueOf(values[0] - values[1]);
            } else {
                result[0] = String.valueOf(values[0] * values[1]);
                symbol = ARITHMETIC_SYMBOLS[2];
            }
        } else if (ARITHMETIC_SYMBOLS[2].equals(symbol)) {
            result[0] = String.valueOf(values[0] * values[1]);
        } else if (ARITHMETIC_SYMBOLS[3].equals(symbol)) {
            if (values[1] != 0 && values[0] % values[1] == 0) {
                result[0] = String.valueOf(values[0] / values[1]);
            } else {
                result[0] = String.valueOf(values[0] + values[1]);
                symbol = ARITHMETIC_SYMBOLS[0];
            }
        }
        result[1] = symbol;
        return result;
    }

    public static Map<String, String> generateArithmeticVerifyCode() {
        StringBuilder code = new StringBuilder();
        int[] values = getNumber();
        String[] result = getResult(values);
        code.append(values[0]).append(result[1]).append(values[1]);
        Map<String, String> map = new HashMap<>();
        map.put("code", code.append(EQUALS).toString());
        map.put("result", String.valueOf(result[0]));
        return map;
    }

    /**
     * 使用系统默认字符源生成验证码
     *
     * @param verifySize 验证码长度
     * @return
     */
    public static String generateVerifyCode(int verifySize) {
        return generateVerifyCode(verifySize, VERIFY_CODES);
    }

    /**
     * 使用指定源生成验证码
     *
     * @param verifySize 验证码长度
     * @param sources    验证码字符源
     * @return
     */
    public static String generateVerifyCode(int verifySize, String sources) {
        if (sources == null || sources.length() == 0) {
            sources = VERIFY_CODES;
        }
        int codesLen = sources.length();
        Random rand = new Random(System.currentTimeMillis());
        StringBuilder verifyCode = new StringBuilder(verifySize);
        for (int i = 0; i < verifySize; i++) {
            verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
        }
        return verifyCode.toString();
    }

    /**
     * 输出指定验证码图片流
     *
     * @param w      宽
     * @param h      高
     * @param os     输出流
     * @param code   验证码
     * @param isMath 是否是数字验证码
     * @throws IOException io异常
     */
    public static void generateImg(int w, int h, OutputStream os, String code, boolean isMath) throws IOException {
        int verifySize = code.length();
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = image.createGraphics();
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        // 设置边框色
        g2.setColor(Color.GRAY);
        g2.fillRect(0, 0, w, h);

        Color c = getRandColor(200, 250);
        // 设置背景色
        g2.setColor(c);
        g2.fillRect(0, 2, w, h - 4);

        // 绘制干扰线
        Random random = new Random();
        // 设置线条的颜色
        g2.setColor(getRandColor(160, 200));
        for (int i = 0; i < 20; i++) {
            int x = random.nextInt(w - 1);
            int y = random.nextInt(h - 1);
            int xl = random.nextInt(6) + 1;
            int yl = random.nextInt(12) + 1;
            g2.drawLine(x, y, x + xl + 40, y + yl + 20);
        }

        // 添加噪点
        // 噪声率
        float yawpRate = 0.05f;
        int area = (int) (yawpRate * w * h);
        for (int i = 0; i < area; i++) {
            int x = random.nextInt(w);
            int y = random.nextInt(h);
            int rgb = getRandomIntColor();
            image.setRGB(x, y, rgb);
        }
        // 使图片扭曲
        shear(g2, w, h, c);

        g2.setColor(getRandColor(100, 160));
        int fontSize = h - 4;
        Font font = new Font("Algerian", Font.ITALIC, fontSize);
        g2.setFont(font);
        char[] chars = code.toCharArray();
        if (isMath) {
            //数字验证码文字不翻转
            for (int i = 0; i < verifySize; i++) {
                g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
            }
        } else {
            for (int i = 0; i < verifySize; i++) {
                AffineTransform affine = new AffineTransform();
                affine.setToRotation(Math.PI / 4 * random.nextDouble() * (random.nextBoolean() ? 1 : -1),
                        (w / verifySize) * i + fontSize / 2, h / 2);
                g2.setTransform(affine);
                g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
            }
        }


        g2.dispose();
        ImageIO.write(image, "jpg", os);
    }



    /**
     * @description: 生成对应类型的验证码
     * @author: feige
     * @date: 2021/6/6 15:40
     * @param	isMath 是否是数字验证码
     * @return: java.lang.String
     */
    public static Map<String, String> generateImg(boolean isMath){
        Map<String, String> result = new HashMap<>();
        try (ByteArrayOutputStream stream = new ByteArrayOutputStream()) {
            if (isMath) {
                Map<String, String> map = generateArithmeticVerifyCode();
                String code = map.get("code");
                result.put("result",map.get("result"));
                generateImg(W, H, stream, code, true);
            } else {
                String code = generateVerifyCode(4);
                result.put("result",code);
                generateImg(W, H, stream, code, false);
            }
            result.put("img", Base64.encode(stream.toByteArray()));
            return result;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    private static Color getRandColor(int fc, int bc) {
        if (fc > 255) {
            fc = 255;
        }
        if (bc > 255) {
            bc = 255;
        }
        int r = fc + random.nextInt(bc - fc);
        int g = fc + random.nextInt(bc - fc);
        int b = fc + random.nextInt(bc - fc);
        return new Color(r, g, b);
    }

    private static int getRandomIntColor() {
        int[] rgb = getRandomRgb();
        int color = 0;
        for (int c : rgb) {
            color = color << 8;
            color = color | c;
        }
        return color;
    }

    private static int[] getRandomRgb() {
        int[] rgb = new int[3];
        for (int i = 0; i < 3; i++) {
            rgb[i] = random.nextInt(255);
        }
        return rgb;
    }

    private static void shear(Graphics g, int w1, int h1, Color color) {
        shearX(g, w1, h1, color);
        shearY(g, w1, h1, color);
    }

    private static void shearX(Graphics g, int w1, int h1, Color color) {

        int period = random.nextInt(2);

        boolean borderGap = true;
        int frames = 1;
        int phase = random.nextInt(2);

        for (int i = 0; i < h1; i++) {
            double d = (double) (period >> 1)
                    * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);
            g.copyArea(0, i, w1, 1, (int) d, 0);
            if (borderGap) {
                g.setColor(color);
                g.drawLine((int) d, i, 0, i);
                g.drawLine((int) d + w1, i, w1, i);
            }
        }

    }

    private static void shearY(Graphics g, int w1, int h1, Color color) {
        // 50
        int period = random.nextInt(40) + 10;

        boolean borderGap = true;
        int frames = 20;
        int phase = 7;
        for (int i = 0; i < w1; i++) {
            double d = (double) (period >> 1)
                    * Math.sin((double) i / (double) period + (6.2831853071795862D * (double) phase) / (double) frames);
            g.copyArea(i, 0, 1, h1, 0, (int) d);
            if (borderGap) {
                g.setColor(color);
                g.drawLine(i, (int) d, i, 0);
                g.drawLine(i, (int) d + h1, i, h1);
            }

        }
    }
}
